Life Sciences Commons^™

Conformation Of The U12-U6atac Snrna Complex Of The Minor Spliceosome And Binding By Ntc-Related Protein Rbm22, Joanna Ciavarella

Dissertations, Theses, and Capstone Projects

Splicing of precursor messenger (pre-m)RNA is a critical process in eukaryotes in which the non-coding regions, called introns, are removed and coding regions, or exons, are ligated to form a mature mRNA. This process is catalyzed by the spliceosome, a multi-mega Dalton ribonucleoprotein complex assembled from five small nuclear ribonucleoproteins (snRNP) in the form of small nuclear (sn)RNA-protein complexes (U1, U2, U4, U5 and U6) and >100 proteins. snRNA components catalyze the two transesterification reactions while proteins perform critical roles in assembly and rearrangement. U2 and U6 snRNAs are the only snRNAs directly implicated in catalyzing the splicing of pre-mRNA. …

Applications Of Nuclear Magnetic Resonance Spectroscopy: From Drug Discovery To Protein Structure And Dynamics., Mark Vincent C. Dela Cerna

Electronic Theses and Dissertations

The versatility of nuclear magnetic resonance (NMR) spectroscopy is apparent when presented with diverse applications to which it can contribute. Here, NMR is used i) as a screening/ validation tool for a drug discovery program targeting the Phosphatase of Regenerating Liver 3 (PRL3), ii) to characterize the conformational heterogeneity of p53 regulator, Murine Double Minute X (MDMX), and iii) to characterize the solution dynamics of guanosine monophosphate kinase (GMPK). Mounting evidence suggesting roles for PRL3 in oncogenesis and metastasis has catapulted it into prominence as a cancer drug target. Yet, despite significant efforts, there are no PRL3 small molecule inhibitors …

The Synthesis And Characterization Of Ionic Liquids Using Nitrogen-Based Cations For Transdermal Delivery, Jo Galloway

Honors Theses

The purpose of this research was to explore the synthesis mechanisms of water-soluble ionic liquids with nitrogen-containing cationic bases for future use in transdermal drug delivery and forensic science applications. Ionic liquids are salts with an organic cation and either an organic or inorganic anion. They have asymmetric structures, which means that the molecules don’t pack together as neatly as other salts do, therefore, they don’t crystallize as easily, and their melting points are lower. Ionic liquids have melting points below 100°C, and many are liquid at room temperature. Mechanistic studies reveal that the potency of ILs in enhancing transdermal …

Paddling Along The Voltage Gated Sodium Channel Galaxy With Sea Anemone Toxins: Structural Studies Of The Interaction Between The Paddle Motif From Nav1.5div And Sea Anemone Toxin, Adel K. Hussein

Dissertations, Theses, and Capstone Projects

Voltage gated sodium channels (VGSC) are membrane proteins that serve an important function in the central nervous system (CNS), peripheral nervous system (PNS), and cardiac muscles amongst others. The main function of VGSC is in the propagation of electrical signals by depolarizing excitable cells. Nine mammalian VGSC subtypes have been characterized, Na_V1.1 – Na_V1.9, that are expressed in a tissue specific manner, each with unique gating properties. Numerous diseases have been linked to defects in VGSC including epilepsy, mental retardation, long QT syndrome, and Brugada disease. Furthermore, these channels are one of the primary targets of …

Investigation Of Interactions Between 1,3 Dialkyl Imidazolium Ionic Liquids And Lignocellulosic Polymers, Aparna Annamraju

Doctoral Dissertations

Lignocellulosic biomass is a potential energy source for fuels, chemicals and materials production in a sustainable manner. A network of covalent and non-covalent bonds between the three main polymers of biomass, i.e., cellulose, hemicellulose and lignin, results in a compact structure that is resistant to chemical and biological attacks and therefore challenging for the efficient utilization of lignocellulosic biomass. Ionic liquids (ILs) have been reported to disrupt the bonds between these polymers and dissolve biomass at temperatures below 100 ˚C. Research through the years has shown that biomass pretreatment with IL brings out the selective dissolution of biomass polymers and …

Investigations Of The Structure And Protein-Protein Interactions Of Chlamydia Trachomatis Scc4, Thilini Oshadhi Senarath Ukwaththage

LSU Doctoral Dissertations

Chlamydia trachomatis (CT) is the most common, sexually transmitted bacterial disease (STD) in the world. In the developmental cycle of CT, specific chlamydia chaperone 4 (Scc4) is a unique protein with essential and multiple roles. Hence, Scc4 is significant as a virulence target for therapeutic approaches to treat chlamydial infections. A novel approach was discovered to purify tag free Scc4 by utilizing a 6X-histidine-tag on Scc1 in the co-expressed Scc4:Scc1 complex by capturing the complex on nickel-charged immobilized metal affinity chromatography resin, followed by dissociation of Scc4 with sarkosyl. Using triple resonance NMR experiments, backbone and sidechain resonances …

Investigating The Disorder And Compaction Of Designed Minielastin Using Nuclear Magnetic Resonance., Ma Faye Charmagne Aquino Carvajal

Electronic Theses and Dissertations

Minielastins are elastin-based proteins with alternating hydrophobic and cross-link modules similar to tropoelastin. Tropoelastin is the ~70 kDa soluble monomeric precursor of elastin. The extracellular matrix protein, elastin provides elasticity to tissues and organs such as lungs, arteries and ligaments. The elastic properties of natural elastin are believed to be entropic in origin. In vivo, the elastin matrix is approximately 50% water by weight. Without water, elastin is brittle and hard. Minielastins, like tropoelastin, undergo a liquid-liquid phase transition upon an increase in temperature. Factors such as hydrophobicity, chain length and concentration affect the coacervation temperature, T_c. The …

Posttranslational Modification And Protein Disorder Regulate Protein-Protein Interactions And Dna Binding Specificity Of P53, Robin Levy

USF Tampa Graduate Theses and Dissertations

p53 is an intrinsically disordered transcription factor that suppresses tumor development by arresting the cell cycle and promoting DNA repair. p53 deletions or mutations can lead to cancer due to the inability of cells to respond to stress. The protein levels and post-translational modification state of p53 changes in response to cellular stress like DNA damage. Previous studies have shown that p53 can undergo coupled folding and binding with the E3 ubiquitin ligase, Mdm2, and the histone deacetylase, p300. In normal cells, p53 is kept at a low level by Mdm2, which marks it with ubiquitin, targeting p53 for proteasome …

Lipoprotein Discordance: Associations With Diabetes, Metabolic Syndrome, And Response To Exercise, Jonathan Joseph Pulama Kupaianaha Ruiz-Ramie

Theses and Dissertations

Purpose: To compare baseline CVD risk factor profiles among groups of individuals with discordant levels of high- and low-density lipoprotein cholesterol (HDL-C and LDL-C respectively) compared to lipoprotein particle concentration (HDL-P and LDL-P respectively) and examine the associations between lipoprotein discordance and incident type 2 diabetes mellitus (T2D) and metabolic syndrome (MetS). Furthermore, to examine the association between lipoprotein discordance and exercise induced changes in CVD risk factors.

Methods: Standard lipid panels as well as lipoprotein subclass profiles via nuclear magnetic resonance spectroscopy were measured among three previously completed studies (CARDIA cohort, HERITAGE Family Study, and HART-D study) spanning over …

Structure And Bioactivity Of A Rationally Designed Nicotinic Acetylcholine Receptor Antagonist Targeting The Alpha-3 Beta-2 Subtype, Leanna Marquart

Boise State University Theses and Dissertations

The work presented in this thesis contributes to ongoing development of an efficient workflow for identification of lead compounds, based on the molecular scaffold of α-conotoxin MII, for drug therapies targeting nicotinic acetylcholine receptors. Nicotinic acetylcholine receptors (nAChRs) are pentameric, ligand-gated ion channels with distribution throughout the central nervous system and are implicated in a variety of neurological diseases including schizophrenia, nicotine addiction, Alzheimer’s disease, and Parkinson’s disease. However, ligand effect on nAChR function is not well understood. Consequently, drug therapies for neurological diseases either do not exist, or have short-lasting efficacy and/or severe side effects. Barriers to the comprehension …

Conserved Glycine Residues Control Transient Helicity And Disorder In The Cold Regulated Protein, Cor15a, Oluwakemi Sowemimo

USF Tampa Graduate Theses and Dissertations

COR15A is a cold regulated disordered protein from Arabidopsis thaliana that contributes to freezing tolerance in plants by protecting membranes. It belongs to the (LEA) Late Embryogenesis Abundant group of proteins that accumulate during the later stage of seed development and are expressed in various parts of the plant. During freezing-induced cellular dehydration, COR15A transitions from a disordered structure to a mostly α-helical structure that binds and stabilizes chloroplast membranes when cells dehydrate due to freezing. We hypothesize that increasing the transient α-helicity of COR15A under normal conditions will increase its ability to bind and protect chloroplast membranes when cells …

Chemoreceptor Dynamics And Signaling: Nmr Measurements Within Functional Complexes, Maryam Kashefi

Doctoral Dissertations

Bacteria employ remarkable membrane-bound nanoarrays to sense their environment and direct their swimming. Arrays consist of chemotaxis receptor trimers of dimers that are bridged at their membrane-distal tips by rings of two cytoplasmic proteins, a kinase CheA and a coupling protein CheW. It is widely accepted that ligand binding to the receptor causes a 2 Å piston motion of a helix that extends through the periplasmic and transmembrane domains. However, it is not clear how the signal propagates 200 Å further to control activity of the kinase bound at the tip of the receptor. Dynamic changes within the cytoplasmic domain …

Structural Studies On Calcium/Calmodulin-Dependent Activation Of Eukaryotic Elongation Factor 2 Kinase, Kwangwoon Lee

Dissertations, Theses, and Capstone Projects

Eukaryotic elongation factor 2 kinase (eEF-2K) is a key modulator of the rate of protein synthesis. Activated by calcium-loaded calmodulin (Ca²⁺-CaM), eEF-2K phosphorylates its only known physiological substrate, eEF-2, on a specific threonine residue (Thr-56). Phosphorylated eEF-2 has reduced affinity for the ribosome, and results in a significant decrease in the rate of translation elongation. Modulation of the rate of translation elongation plays a crucial role in proteostasis – adequate regulation of protein synthesis, protein folding, and protein degradation that greatly influences cellular growth and survival. Binding of Ca²⁺-CaM triggers activation of eEF-2K and remains intact …

Automatic 13C Chemical Shift Reference Correction Of Protein Nmr Spectral Data Using Data Mining And Bayesian Statistical Modeling, Xi Chen

Theses and Dissertations--Molecular and Cellular Biochemistry

Nuclear magnetic resonance (NMR) is a highly versatile analytical technique for studying molecular configuration, conformation, and dynamics, especially of biomacromolecules such as proteins. However, due to the intrinsic properties of NMR experiments, results from the NMR instruments require a refencing step before the down-the-line analysis. Poor chemical shift referencing, especially for ¹³C in protein Nuclear Magnetic Resonance (NMR) experiments, fundamentally limits and even prevents effective study of biomacromolecules via NMR. There is no available method that can rereference carbon chemical shifts from protein NMR without secondary experimental information such as structure or resonance assignment.

To solve this problem, we …

Biophysical Exploration Of Conformational Environments In Zymogen Prothrombin And Blood Coagulant Thrombin., Ramya Billur

Electronic Theses and Dissertations

The serine protease thrombin plays important roles in coagulation, anticoagulation, and platelet activation. Thrombin is initially expressed as the inactive zymogen prothrombin (ProT). The final cleaved and activated form of thrombin has mature anion binding exosites (ABEs) and several regulatory loops. Engagement with these exosites helps define the fate of thrombin as a procoagulant or an anticoagulant. Researchers previously reported that zymogen ProT may already bind exosite ligands. Little is known about conformational changes associated with ProT maturation, resultant ligand binding affinities, individual ligand-protein contacts, and long-range communication between thrombin exosites. Protease Activated Receptors (PARs) play critical roles in controlling …

Structure Of The Picornavirus Replication Platform: A Potential Drug Target For Inhibiting Virus Replication, Meghan Suzanne Warden

Chemistry & Biochemistry Theses & Dissertations

Picornaviruses are small, positive-stranded RNA viruses, divided into twelve different genera. Members of the Picornaviridae family cause a wide range of human and animal diseases including the common cold, poliomyelitis, foot and mouth disease, and dilated cardiomyopathy. The picornavirus genome is replicated via a highly conserved mechanism involving a presumed cloverleaf structure located at the 5’ noncoding region of the virus genome. The 5’ cloverleaf consists of three stem loops (B, C, and D) and one stem (A), which interact with a variety of virus and host cell proteins during replication. In this dissertation, human rhinovirus serotype 14 (HRV-14) SLB …

Insight Into The Interaction Between The Peroxisome Proliferator-Activated Receptor Gamma (Pparγ) And Adipocyte Fatty Acid-Binding Protein (A-Fabp), Qian Wang

Dissertations, Theses, and Capstone Projects

The Adipocyte Fatty Acid-Binding Protein (AFABP) is mainly expressed in fat cells. It can bind fatty acids and other lipophilic substances such as eicosanoids and retinoids. The peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor protein that requires ligand binding to regulate the specific gene transcription. PPARγ is expressed at extremely high levels in adipose tissue, macrophages, and the large intestine, where it controls lipid adipogenesis and energy conversion. Moreover, it has been found that AFABP and PPARγ can form a complex in vivo. It is proposed that AFABP carries the ligand and enters into the nucleus where it …

Algorithms For Automated Assignment Of Solution-State And Solid-State Protein Nmr Spectra., Andrey Smelter

Electronic Theses and Dissertations

Protein nuclear magnetic resonance spectroscopy (Protein NMR) is an invaluable analytical technique for studying protein structure, function, and dynamics. There are two major types of NMR spectroscopy that are used for investigation of protein structure – solution-state and solid-state NMR. Solution-based NMR spectroscopy is typically applied to proteins of small and medium size that are soluble in water. Solid-state NMR spectroscopy is amenable for proteins that are insoluble in water. In the vast majority NMR-based protein studies, the first step after experiment optimization is the assignment of protein resonances via the association of chemical shift values to specific atoms in …

Mri T2 Signal Changes Indicate Tau Pathophysiology In A Murine Alzheimer's Disease Model, Rajan Deep Adhikari

Theses and Dissertations

Pathogenesis, diagnosis and treatment, the essential domains in medical practice, seem helpless to address Alzheimer's disease (AD). With a huge mortality rate, it is looming and threatening the socioeconomic barrier. Despite many different studies, the pathogenesis of AD remains inconclusive. However, growing numbers of studies suggest oxidative stress to contribute to the initiation and progression of AD. We propose an iron hypothesis: iron mediated oxidative damage by reactive oxygen species (ROS), which induces protective roles of amyloid beta and hyper-phosphorylated tau (HP-tau) to sequester iron and limit the disease. We propose to study such mechanism using transgenic mice models for …

Autoinhibition And Activation Of Parkin, Jacob D. Aguirre

Electronic Thesis and Dissertation Repository

Mutations in the gene encoding parkin, an E3-ubiquitin ligase, result in 50% of Autosomal Recessive Juvenile Parkinsonism cases. Parkin has been identified as a key mediator of mitochondrial regeneration following oxidative stress, and pathogenic mutations have been shown to impair its ubiquitin ligase activity. Neurodegeneration of dopamine-producing neurons appears to be a downstream consequence of parkin loss-of-function, resulting in early-onset forms of Parkinson’s disease. Although ubiquitination activity is essential for its neuroprotective function, parkin is autoinhibited in its native state by various mechanisms, including its N-terminal ubiquitin-like (UBL) domain. Therefore, the overarching objective of this thesis was to structurally characterize …

Structural Characterization Of The Interactions Of Nicotinamide And Analogs With Human Sirt6 By Saturation Transfer Difference (Std) Nmr And Site Directed Mutagenesis, Beatriz Elena Bolivar-Vega

Legacy Theses & Dissertations (2009 - 2024)

The allosteric regulation of SIRT6 by nicotinamide (NAM), along with the growing evidence of this enzyme's key role in the immune response, prompted the mechanistic study of SIRT6 inhibition by pyrazinamide (PZA) and analogs. In our current study, PZA, an analog of NAM, was revealed to have a modest modulatory effect on SIRT6, an enzyme that regulates the NF-κB signaling pathway at the transcriptional level (a relevant pathway to inflammation). Similarly, the analogs of PZA, 5-Cl PZA, 5-MeO PZA, and POA exhibited a modulatory effect against SIRT6 in our in vitro studies, enabling identification of a potential new target for …

Interaction Of Spliceosomal U2 Snrnp Protein P14 With Its Branch Site Rna Target, William Perea Vargas

Dissertations, Theses, and Capstone Projects

Newly transcribed precursor messenger RNA (pre-mRNA) molecules contain coding sequences (exons) interspersed with non-coding intervening sequences (introns). These introns must be removed in order to generate a continuous coding sequence prior to translation of the message into protein. The mechanism through which these introns are removed is known as pre-mRNA splicing, a two-step reaction catalyzed be a large macromolecular machine, the spliceosome, located in the nucleus of eukaryotic cells. The spliceosome is a protein-directed ribozyme composed of small nuclear RNAs (snRNA) and hundreds of proteins that assemble in a very dynamic process. One of these snRNAs, the U2 snRNA, is …

Structure And Dynamics Of A Small Multidrug Resistance Transporter, Emre, Chao Wu

Arts & Sciences Electronic Theses and Dissertations

EmrE is a small multidrug resistance transporter in E. coli. It effluxes a wide range of antibiotics, thus contributing to the evolving epidemic of drug resistance. Despite its small size, EmrE is a fully functional transporter making it an ideal model system for a comprehensive study of the multidrug transport mechanism. In the transport cycle, EmrE must alternate between outward- and inward-facing conformations upon substrate binding to translocate substrates across the membrane. High-resolution structures of EmrE in complex with substrates facing different sides of the membrane will shed light on the coupling mechanism between substrate binding and transport. However, the …

Computational Modeling Of Rna-Small Molecule And Rna-Protein Interactions, Lu Chen

Dissertations & Theses (Open Access)

The past decade has witnessed an era of RNA biology; despite the considerable discoveries nowadays, challenges still remain when one aims to screen RNA-interacting small molecule or RNA-interacting protein. These challenges imply an immediate need for cost-efficient while predictive computational tools capable of generating insightful hypotheses to discover novel RNA-interacting small molecule or RNA-interacting protein. Thus, we implemented novel computational models in this dissertation to predict RNA-ligand interactions (Chapter 1) and RNA-protein interactions (Chapter 2).

Targeting RNA has not garnered comparable interest as protein, and is restricted by lack of computational tools for structure-based drug design. To test the potential …

Gallic Acid-Grafted Chitosan Films As Antioxidant Food Packaging, Ping Guo

Masters Theses

Chitosan is the second most abundant natural polysaccharide in the nature. Due to its biodegradability and film forming ability, chitosan has the potential to be used as an alternative to petroleum-based polymers for food packaging. The presence of a primary amine as well as primary and secondary hydroxyl groups enable chitosan to be chemically modified with various functional groups. Gallic acid (GA) is a natural occurring antioxidant (AOX), which can be grafted to chitosan using by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The first project deals with the effect of ethanol (EtOH) concentration on efficiency of grafting GA onto chitosan. …

Structural Elucidation Of Aggr-Activated Regulator, Aar, In Enteroaggregative Escherichia Coli, Andrew Heindel

Senior Honors Projects, 2010-2019

Travelers’ Diarrhea is the number one cause of childhood death in the world. Enteroaggregative Escherichia coli (EAEC) is one of the main causes of this disease. EAEC adhere to the surface of the intestine and stack in a brick-like pattern. Via an unstudied quorum-sensing mechanism, these bacteria express a variety of virulence factors that lead to diarrhea. The long-term goal of this research is to elucidate the mechanism by which EAEC changes from benign to virulent. A previously-unstudied open-reading frame in EAEC, AggR activated repressor (Aar), has recently been hypothesized to act as one of the major transcription factors influencing …

Conformational Heterogeneity And Exchange Within The Junction Of The Human U2-U6 Snrna Complex Measured By 19f Nmr Spectroscopy, Caijie Zhao

Dissertations, Theses, and Capstone Projects

Pre-mRNA splicing, the process by which non-coding sequences are removed and coding sequences are ligated, plays an important role in the maturation of precursor messenger RNA molecules prior to their translation into proteins. In eukaryotes, splicing is catalyzed by the spliceosome, a large and dynamic nuclear macromolecular "machine" that comprises five small nuclear (sn)RNA molecules and more than one hundred proteins. Among the RNA components, the complex formed between the U2 and U6 snRNA molecules is implicated in catalytic activity. In this dissertation, I have used ¹⁹F NMR techniques to characterize the conformation ("fold") and dynamics of a protein-free …

Sharp Rna Recognition Motif Optimizations, Extensions, And Mutations For Use In 2d And 3d Nmr Experiments, Shaun M. Christie

Williams Honors College, Honors Research Projects

SMRT/HDAC Associated Repressor Protein interacts with the long noncoding RNA, produced by SRA, by binding at the RRMs. Three projects were done to prepare the truncated proteins for use in 2D and 3D NMR experiments. The first focuses on RRM 3 and its optimization during the purification process. The second focuses on RRM 2-4, which was found to be missing two alpha helices that may be important for protein stability. These helices can also interact with RRM 3 as well due to the tight association of RRMs 3 and 4. The two step PCR extension of RRM 2-4 was assumed …

Carbon Storage And Preservation In Seagrass Meadows, Mohammad Rozaimi Jamaludin

Theses: Doctorates and Masters

Seagrass meadows are important ‘Blue Carbon’ sinks but many questions remain unaddressed in regards to the organic carbon (OC) sequestration capacity and processes leading to retention and persistence of OC in seagrass sediments. The research summarised in this dissertation examined 37 sediment cores from twelve Australian seagrass meadows (Posidonia australis and Halophila ovalis) in order to improve our understanding of OC storage and preservation in seagrass sediments. The research: quantified the OC storage in seagrass meadows and the reduction in stores after ecosystem degradation; the rates of OC accumulation; the roles of species composition and the depositional nature …

Profiling Fatty Acid Composition Of Brown Adipose Tissue, White Adipose Tissue And Bone Marrow Adipose Tissue Of Healthy And Diet-Induced Obese Mice, Urszula Osinska Warncke

Browse all Theses and Dissertations

Bone marrow adipose tissue (MAT) contains a fat depot of unknown function. Characterization of this tissue in healthy and pathophysiological conditions may be an important step in order to understand MAT contribution to development of osteoporosis and perhaps to develop means to improve bone health by manipulation with a phenotype of MAT. Here we demonstrate that MAT, brown adipose tissue (BAT), and white adipose tissue (WAT) derived from healthy mice differ in fatty acid and phospholipid composition. The profile of MAT changed to resemble a less-metabolically active tissue upon metabolic impairment as seen in diet-induced obesity. Additionally, PPARγ activation alters …